A closed-loop renewable energy evaluation framework

Many businesses that have embraced renewable energy projects as part of their corporate sustainability efforts lack direction concerning how the projects are assessed. This study presents a framework that prescribes the necessary stages that allow a robust project evaluation to take place. The framework should assist practitioners in ascertaining if renewable energy projects, such as wind turbines and hydro-electric generators, contribute to energy cost savings and a reduction in CO₂ emissions. The conceptual framework was developed using empirical data accessed from an 850-kW wind turbine case study and a 40-kW hydro-electric case study and embraced the action research methodology. Both renewable projects are based in Ireland. The 850-kW wind turbine project was found to display disappointing results. As part of the electrical generator power quality measurement, it was found that there was large dispersion in the wind turbine output signal where the coefficient of variation values of between 128% and 939% were recorded. The simple payback period for the wind turbine investment is 7.34 years. The assessment of the 40-kW hydro-electric project found that positive values could be attributed to the environmental, economic, and social aspects of the project. Coefficient of variation values of between 2.8% and 3.9% were calculated for the hydro-electric plant with a simple payback period of fewer than two years. It was found that the dispersion value affects the actual financial and environmental benefits of the project. This is the first time that the short-term dispersion characteristic of a renewable generator power output signal is considered as part of the power quality analysis. Measurement of the quality of renewable power outputs should include the short-term ramping, dispersion, characteristic of the power signal. An implication for stakeholders is that the short-term ramping variation of renewable energy generators must be measured in each evaluation process.